In business, government, academic and home applications, the widespread need for interconnectivity among a diverse variety of user devices such as mobile phones, personal computers, personal digital assistants (PDA), etc. to communications infrastructure has driven the widespread usage of wireless communication networks. Wireless networks offer the distinct advantages of rapid deployment, tetherless access, ad-hoc topology, and user mobility. On the other hand, wireless networks are often restricted in user data rate and coverage area by co-channel interference. Wireless communication systems also must carefully manage their spectral utilization since the radio spectrum is a scarce resource in most geographical areas.
One form of wireless communication networks is known as a wireless local area network (WLAN). WLANs provide network connectivity without wired connection over a local area such as an office floor, factory, school, airport, coffee shop, outdoor plaza, etc. The coverage radius of a WLAN access point is usually less than 300 m. One commonly used wireless network standard is based on the IEEE 802.11 protocol, also known as WiFi. The 802.11 protocol consists of a family of wireless protocols with different modulation techniques and data rates all operating within the 2.4 GHz or 5 GHz bands or any other bands allowed by the IEEE 802.11 specification.